Stamping press

ABSTRACT

Press includes two subunits incorporating each a cylinder, piston, and a tool holder and independently removable from the press frame by removing tension bolts and knocking out supporting wedges.

Unite States Patet Inventors Appl. No. Filed Patented Assignee Priority Walter Wanner Romanshorn;

llleinz Lampert, Buchs, both of, Switzerland Apr. 30, 1969 Aug. 17, 1971 Hydrel A.G.

Romanshorn, Switzerland May 2, 1968 Switzerland 6530/68 STAMPING PRESS 13 Claims, 4 Drawing Figs.

US. Cl Int. Cl

Field of Search [56] References Cited UNITED STATES PATENTS 545,758 9/1885 Aiken 72/455 3,321,952 5/1967 Wagner 72/453 FOREIGN PATENTS 937,635 9/1963 Great Britain 72/456 Primary Examiner-Charles W. Lanham Assistant Examiner-Gene P. Crosby Attorney-Singer, Stern & Carlberg ABSTRACT: Press includes two subunits incorporating each a cylinder, piston, and a tool holder and independently removable from the press frame by removing tension bolts and knocking out supporting wedges.

PATENTED Am; r 7 m1 SHEET 2 BF 2 Fig.2

STAMPING PRESS BACKGROUND OF THE INVENTION This invention relates to a press having a frame mounting two relatively movable tool holders. The press, for example, can be a precision stamping press having a vertically movable lower tool-holding table operated by a piston in a cylinder and an upper tool-holding table rigidly mounted in the frame.

SUMMARY OF THE INVENTION The purpose of the invention is to facilitate the assembly and disassembly of presses, an advantage of some importance with mechanical presses, but of particular significance with hydraulic presses, which have gaskets, positioned between the cylinder and piston, that must be replaced periodically.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be described, with reference to the Figures of the accompanying drawings, wherein:

FIG. I is a diagrammatic view in partial vertical section of an embodiment of the invention;

FIG. 2 is a top view ofthe embodiment shown in FIG. 1;

FIG. 3 is a sectional view on expanded scale of a detail of the embodiment shown in FIG. 1; and

FIG. 4 is a bottom view on enlarged scale ofa guide cone.

DESCRIPTION OF THE PREFERRED EMBODIMENT With reference to the Figures, the illustrated precision stamping press has two oppositely disposed uprights 1, between which two easily dismountable parts, an upper subunit 2 and a lower subunit 3, are held. The two uprights are connected together at the top and bottom by respective pairs of horizontal tension bolts 4 and nuts 5.

The upper part 2 comprises a hydraulic cylinder 6 having an auxiliary piston 7 composed of a crown 7a and a cylindrical body 7b held together by a ring of bolts 8. A connection hole 9 for an oil line (not shown) leads to the interior 10 of the cylinder. The piston 7 is precisely guided in its stroke by two guide arrangements 11 and 12, the latter being shown on en- Iarged scale in FIG. 3. The two guide arrangements will be explained in detail.

The cylinder 6 consists of an upper part 6a and a lower part, or flange, 6b held together by a ring of bolts 13. The upper part 6a is constructed as a round body, but the flange 612 has only a round internal bore, whereas its outer part constitutes a rectangular flange projecting beyond the outer face of the upper part 6a. Two oppositely disposed sides 14 of the flange 6b engage in guideways 15 provided in the uprights I and rest on two gently sloping wedges 16, also held in the guideways. The front ends 16a (see FIG. 2) of these wedges are slightly lower than the rear ends 16b, and the lower supporting surfaces 17 of the flange 617 or the'upper supporting surface 18 of the guideways 15 or both of these surfaces are oppositely slanted a number of degrees equal to that of the wedge angle. The front ends 16a of the wedges 16 are provided with suitable means, such as the cotters 19, for holding the wedges in place.

To remove the upper part 2, the latter first of all must be hung from a travelling crane or supported on a fork lift, in a manner not shown. After removing the cotters 19, the wedges 16 are knocked out of the guideways l5 and withdrawn. Next, the upper bolts 4 are removed, enabling the subunit 2 to be moved backwards or forwards horizontally until the flange 6 is free of the guide ways 15, completely freeing the subunit 2 from the uprights 1. When assembling the subunit 2 on the upright, the sequence of steps, of course, is reversed.

In addition to the cylinder 6 and piston 7, the subunit 2 also comprises an upper tool holding table 20, which a ring of bolts 21 and spacers 22 hold fixed at a certain distance from the flange 6b. The piston 7 is shown in FIG. 1 in its lowest position, resting on a plate 23, which lies loosely on the table and is connected in a known manner by bolts (not shown) passing through openings in the table 20 with a toothed ring not shown) that serves to hold the metal to be stamped, as is customary with precision stamping presses. Although the following details are not essential to an understanding of the invention, in the interest of completeness it is also remarked that when the lower tool-holding table 24, belonging to the subunit 3, rises, the metal resting on the lower cutting tool is first of all pressed against the toothed ring 80, which latter presses against the plate 23 and moves the piston 7 upwards, forcing oil out of the interior of the cylinder 6 against a back pressure that is adjusted by a valve to correspond to the desired toothed ring pressure. The actual stamping operation begins only when the piston 7 through the plate 23, the thrust bolts 81 and the toothed ring rests on the material to be stamped.

The subunit 3 has a hydraulic cylinder 25 comprising an axially symmetrical bottom part 25a and a square flange 25b held together by a ring of bolts 26. Two opposite sides 27 of the flange 25b are held in two guideways 28 of the uprights 1. In these guideways and above the flange .2512, two wedges 16 are arranged in the same manner as explained in connection with the subunit 2. The cylinder bottom part 25a extends into a wall 29 that is provided in the press foundation between the uprights 1 and which extends forwards and/or backwards from the press.

To remove the subunit 3, it is supported on a low truck (not shown) in the well 29, and the lower wedges 16 then removed. The subunit 3 can now be moved forwards or backwards until the flange 25b is free of the guideways 28, and then, if necessary, raised out ofthe well by a crane or similar machine.

The main piston 30 of the press operates in the cylinder 25. The main piston is a trunk piston and forms the hydraulic cylinder for an ejector piston 31. The main piston 30 consists of a crown 30a a body 30b and an upper part 30c all held together by two rings of bolts 32 and 33. The cylinder chambers 34 is connected to a line (not shown) for hydraulic oil by a connection opening 35.

A series of bosses 36 projecting from the piston crown 300 support the piston 30 in its lowest position on the bottom of the cylinder 25. Two guide arrangements 37 and 38, having the same construction as the guide arrangements 11 and 12, precisely guide the piston 30 in its stroke.

The lower tool holding table 24 is rigidly connected to a cylindrical sleeve 39 that surrounds the piston upper part 30c and forms with the latter an annular chamber 40, which, in a manner not illustrated, is connected to a compressed air line for tool protecting, as is well known.

The table 24 is shown in FIG. 1 in its bottom position, resting on the piston upper part 30C.

Between the ejector piston 31 and the table 24 is arranged a loose plate 41, which bolts 42 passing through holes in the table 24 connect in a known manner with an ejector 84 for removing the finished stamped metal part. The ejector piston 31 also acts during the pressing operation as a back pressure piston.

To prevent the main piston 30 from twisting 'luring its stroke, causing the table 24 to score the uprights 1, four guide rollers 43 are mounted on the table 24 and roll on guideways 44 incorporated in the uprights l.

The guide arrangement 12, shown on enlarged scale in FIG. 3, comprises an annular, elastically yielding guide cone 45 surrounded by an annular clamping cone 46, ofwhich the conical inner face 47 defines the same apical angle as the conical outer face 48 of the guide cone 45. Both cones 45 and 46 are held in a cylindrical ring chamber 49 of the flange 6b. This chamber is open at the top. A thin thrust ring 51 is positioned between the bottom 50 of the chamber 49 and the clamping cone 46. A gasket 52 for sealing thepiston 7 from the cylinder 6 is held in a smaller cylindrical ring chamber provided below the chamber 49 in the flange 6b. The cylindrical inner face of the guide cone 45 has a low-friction synthetic plastic lining 53, which presses against, and guides the movement of, the piston cylindrical body 7b. A corresponding synthetic plastic lining 53a is provided on the cylindrical outer face of a guide cone 45a comprised by the guide arrangement 11. The parts rigid with the cylinder and the piston contact each other only on the exposed surfaces of the linings 53 and 53a and of the relatively soft and yielding gasket 52.

-The guide cone 45 is somewhat shorter than the clamping cone 46 and is pressed downwards by a set of stiff cup springs 54. The wedge action of the clamping cone 46 consequently presses inwards on the elasticity yielding guide cone 45, which is caused to press radially against the piston body 7b, as indicated by the arrow. FIG. 4 shows that the elastic yieldingness of the guide cone is chiefly obtained by a series of radial slits 55, which terminates at their outer ends in enlarged recesses 56 and divide the cone 45 into sectors 57 that are connected together only by a thin web at the inner ends of the slits S5.

The upper face of each sector 57 embodies a recess 59 for freely accommodating the head 60 of a screw 61. The screw 61 is turned into the threaded hole 62 of a ring 63 held in an annular opening 64 of the cylinder upper part 6a. The cup springs 54 are arranged on the screws 61 and are located for the most part in a coaxial enlargement 65 of the hole 62. The cup springs are tightly compressed between the screw head 60 and a stop plate 66, when the guide arrangement is assembled. As the bolts 13 are tightened, pressing the ring 63 down on the clamping cone 46, the cup springs 54 come to press against the edge of the recess 59, the screw head 60 entering the recess 59 at least partways and the cup springs 54 pressing downwards on the guide cone 45 with a predetermined force that corresponds to the desired radial guiding force. It is apparent that even when the lining 53 wears, this lining continues to be pressed against the piston body 717, ensuring a guiding that is completely free of play. The same observation holds true for the lining 53a of the guide cone 45a.

The guide arrangement 11 is constructed in substantially the same way as the guide arrangement 12 the corresponding parts being denoted by the same reference numerals with an added sulfix a. The guide cone 451:, however, is not pressed radially inwards against the piston 7, but instead radially out wards against the cylinder 6. A further difference is that there is no annular clamping cone, since the piston crown 7a itself embodies a conical clamping surface 47a. In respect only of the guiding function, the clamping cone 46 can be made as a unitary piece with the flange 6b in the guide arrangement 12. But in this case the gasket 52 is no longer easily accessible. whereas one of the most important grounds for requiring that the subunit 2 is easily taken apart is the very necessity of having to change the gasket 52 from time to time. On the other hand, a small gasket 67, arranged next to the ring 63, is subject to almost no wear.

The parts of the guide arrangements 37 and 38 are denoted by the same reference numerals as the corresponding parts of the respective arrangements 11 and 12, from which they differ only in being turned upside down. Two gaskets 68 and 69 are provided between the cylinder and the main piston 30. Although the gasket 68 corresponds substantially to the gasket 52, the gasket 69 is composed, in a manner conventional but not illustrated, of a pressure-resistant annular mount and of a soft, yielding sealing part, because after each working stroke of the main piston hydraulic oil is let into the annular slot 70 between the piston 30 and the cylinder 25 to press on the armored gasket 69 and the guide arrangement 37 and quickly push the piston 30 down. A connection opening 71 is provided in the cylinder bottom part 25a for connection to the necessary oil line.

The gaskets 68 and 69, as well as the gaskets (not shown) for the ejector piston 31, must be renewed oftener than the gasket 52 in the subunit 2, since the gaskets located in the subunit 3 wear faster because of the high oil pressure and longer piston stroke. Consequently, it is particularly advantageous that the subunit 3 can be taken apart without first having to remove the subunit 2 from the uprights 1.

The described guide arrangements 11,12 and 37, 38 are free of play and in regard of manufacturing cost and satisfactory performance far'more advantageous than the hitherto customary very long and rigid guides having rolling elements. With these previous guide arrangements it would have been scarcely possible so to construct the units 2 and 3 that they can-as described-be removed from the uprights 1 like pulling out a drawer. But it is also apparent that the guide arrangements of the invention are also advantageously used in presses that do not permit the individual parts to be removed like a drawer.

Although the invention has been described in connection with a hydraulic press, it can also be employed with nonhydraulic presses, the easy disassembly for repairs and periodic inspection being advantageous even though no gaskets have to be replaced. The working stroke of the press can be either vertical or horizontal.

The wedges 16, which ensure a rapid connection between the units 2 and 3 and the uprights l in the vertical direction, are not absolutely essential. If the flange guideways l5 and 28 have a wedge-shaped section, it suffices to tighten the nuts 5 on the tension bolts 4 to ensure that the subunits 2 and 3 are rigidly clamped vertically as well as horizontally between the uprights l. The subunits 2 and 3 can also be connected to the uprights 1 by bolts that replace the tension bolts 4.

Although the preferred embodiment of the invention has been described, the scope of, and the breadth of protection afforded to, the invention are limited solely by the appended claims.

We claim:

1. A press, including a frame, two tool holders (20, 24) relatively movable with respect to each other, and wherein the improvement comprises a frame comprising two members, two pairs of oppositely disposed guideways (15, 28) in said two members, two flanges (6b, 2512) having two parallel sides that are held in respective pairs of said guideways, two respective press subunits (2, 3) comprising each a pair ofsaid flanges and a respective said tool holder, and removable fastening elements (4) for clamping the said sides of a respective said flange in the corresponding said guideways, whereby each said subunit can be moved along the corresponding pair of guideways to be removed from, or replaced in, said frame independently of the other by removal ofsaid fastening means.

, 2. The press as defined in claim 1, including a hydraulic cylinder (25) partly formed by one of said flanges (25b, and a piston (30) in said hydraulic cylinder in operative connection with one of said tool holders (24).

3. The press as defined in claim 2, including a second hydraulic cylinder (6) partly formed by the other of said flanges (6b). and an auxiliary piston (7) in said second cylinder, and wherein the first said piston is the main piston of the press.

4. The press as defined in claim 1, wherein said two frame members are spaced uprights, said two press subunits are arranged between said two uprights, and said two work holders are vertically movable relative to each other.

5. The press as defined in claim 3, wherein one of said hydraulic cylinders extends downwards, said two frame members are spaced uprights, said two press subunits are arrangt between said two uprights, and said two work holders are vertically movable relative to each other.

6. The press as defined in claim 1, including wedges (16) positioned between said flanges and said two pa rs of guideways for providing a rigid connection between said press subunits and said two frame members in the lengthwise direction of the latter.

7. The press as defined in claim 1, including reciprocatory member (7, 30) comprised by at least one of said press subunits and movable in the longitudinal direction of said press frame, at least one guide arrangement (11, 12, 37, 38) for guiding said reciprocatory member without play along its path of movement, an annular, elastically yielding guide cone (45, 45a) comprised by said guide arrangement, said guide cone embodying a conical face (48, 48a) and an opposite cylindrical guide face, a conical surface (47, 47a) having the same conieity as said conical face and against which said conical face presses, and means (54, 54a") for exerting an axial force on said guide cone for causing said cylindrical guide face thereof to exert pressure elastically and radially.

8. The pressure as defined in claim 7, including a low-friction lining (53, 53a) for covering said guide-cone cylindrical guide face.

9. The press as defined in claim 7, including radial slits (55) that divide said cone into sectors and make it elastic, and webs (58) for connecting said sectors together.

10. The press as defined in claim 7, wherein said means are cup springs under compression.

1]. The press as defined in claim 7, including an annular clamping cone (46, 46a embodying said conical surface.

12, The press as defined in claim 7, including at least one hydraulic cylinder (6, 25 and wherein said reciprocatory member is a piston movable within said cylinder, and including a pair of said guide arrangements, spaced, for guiding said piston in its stroke, and wherein said guide-cone cylindrical guide face of one of said guide arrangements cooperates with said piston and said guide-cone cylindrical guide face of the other said guide arrangement cooperates with said cylinder.

13. The press as defined in claim 12, including at least one gasket (52, 68, 69) arranged between said cylinder and piston, and wherein one of said flanges partly forms said cylinder, at least two separate parts (6a, 6b, 25a; 7a, 7b; 30a, 30b, 300) for forming each of said piston and said cylinder, and bolts (8, 13, 26, 32, 33) for holding together the said piston and cylinder parts for permitting said gasket to be easily replaced after removal ofsaid subunit from said press frame. 

1. A press, including a frame, two tool holders (20, 24) relatively movable with respect to each other, and wherein the improvement comprises a frame comprising two members, two pairs of oppositely disposed guideways (15, 28) in said two members, two flanges (6b, 25b) having two parallel sides that are held in respective pairs of said guideways, two respective press subunits (2, 3) comprising each a pair of said flanges and a respective said tool holder, and removable fastening elements (4) for clamping the said sides of a respective said flange in the corresponding said guideways, whereby each said subunit can be moved along the corresponding pair of guideways to be removed from, or replaced in, said frame independently of the other by removal of said fastening means.
 2. The press as defined in claim 1, including a hydraulic cylinder (25) partly formed by one of said flanges (25b, ) and a piston (30) in said hydraulic cylinder in operative connection with one of said tool holders (24).
 3. The press as defined in claim 2, including a second hydraulic cylinder (6) partly formed by the other of said flanges (6b). and an auxiliary piston (7) in said secOnd cylinder, and wherein the first said piston is the main piston of the press.
 4. The press as defined in claim 1, wherein said two frame members are spaced uprights, said two press subunits are arranged between said two uprights, and said two work holders are vertically movable relative to each other.
 5. The press as defined in claim 3, wherein one of said hydraulic cylinders extends downwards, said two frame members are spaced uprights, said two press subunits are arranged between said two uprights, and said two work holders are vertically movable relative to each other.
 6. The press as defined in claim 1, including wedges (16) positioned between said flanges and said two pairs of guideways for providing a rigid connection between said press subunits and said two frame members in the lengthwise direction of the latter.
 7. The press as defined in claim 1, including reciprocatory member (7, 30) comprised by at least one of said press subunits and movable in the longitudinal direction of said press frame, at least one guide arrangement (11, 12, 37, 38) ) for guiding said reciprocatory member without play along its path of movement, an annular, elastically yielding guide cone (45, 45a) comprised by said guide arrangement, said guide cone embodying a conical face (48, 48a) and an opposite cylindrical guide face, a conical surface (47, 47a) having the same conicity as said conical face and against which said conical face presses, and means (54, 54a) for exerting an axial force on said guide cone for causing said cylindrical guide face thereof to exert pressure elastically and radially.
 8. The pressure as defined in claim 7, including a low-friction lining (53, 53a) for covering said guide-cone cylindrical guide face.
 9. The press as defined in claim 7, including radial slits (55) that divide said cone into sectors and make it elastic, and webs (58) for connecting said sectors together.
 10. The press as defined in claim 7, wherein said means are cup springs under compression.
 11. The press as defined in claim 7, including an annular clamping cone (46, 46a ) embodying said conical surface.
 12. The press as defined in claim 7, including at least one hydraulic cylinder (6, 25), and wherein said reciprocatory member is a piston movable within said cylinder, and including a pair of said guide arrangements, spaced, for guiding said piston in its stroke, and wherein said guide-cone cylindrical guide face of one of said guide arrangements cooperates with said piston and said guide-cone cylindrical guide face of the other said guide arrangement cooperates with said cylinder.
 13. The press as defined in claim 12, including at least one gasket (52, 68, 69) arranged between said cylinder and piston, and wherein one of said flanges partly forms said cylinder, at least two separate parts (6a, 6b, 25a; 7a, 7b; 30a, 30b, 30c) for forming each of said piston and said cylinder, and bolts (8, 13, 26, 32, 33) for holding together the said piston and cylinder parts for permitting said gasket to be easily replaced after removal of said subunit from said press frame. 